Re: 1951 CD - 9" drum brakes "grabbing"

Jim Liberty

Thanks Brett, I restore 356s too, and you are right on. I always turn my drums, and have the shoes radiused by a brake shop. Full even contact, from day one.    .....Jim.

On Sun, Jul 4, 2021 at 1:34 PM Brett Wright <bwright@...> wrote:
I am going to throw this out because it happened to
Me on a drum brake Porsche 356. If your drums are worn to your shoes from running and your drums have different Inside diameters and you inadvertently swapped them, it will definitely cause the problem you describe. Not only that, it will cause a very severe pull in one direction.

Brett Wright

On Jul 3, 2021, at 3:29 PM, Bob H. via <> wrote:

I think so but would welcome a second opinion. The linings are installed with the longer lining toward the front of the car. I have the passenger side apart again now so I've attached some photos. I also took photos of the lining surfaces in case it's obvious that they're contaminated. 

As for adjustment, I adjusted the top (eccentric pin) first by turning until the drum dragged and then backing off until the dragging stopped (which didn't take much). Then I did the same with the bottom (anchor points). I didn't use feeler gauges; maybe I need to? I have standard feeler gauges like for a valve adjustment but I'm not sure those are right for a curved brake drum surface? 


On Sat, Jul 3, 2021, 3:17 PM Jim Liberty <jimliberty356@...> wrote:
Are you sure the shoes are installed correctly? Sounds like you did the rest correctly. Is it possible the new cylinders are leaking again. It does happen even with new parts.   ...... Jim.

On Sat, Jul 3, 2021 at 12:08 PM Bob H. <bob@...> wrote:
I don't have much experience with drum brakes but the linings didn't look wet or discolored to me. Would it be obvious if they were damaged from fluid? I did very lightly clean them up with some medium sandpaper before reassembly just to remove any extra dust.

Thanks a lot for your help!


On Sat, Jul 3, 2021, 2:51 PM Jim Liberty <jimliberty356@...> wrote:
Did you check the linings for brake fluid. The leak may have contaminated them.    ......Jim.

On Sat, Jul 3, 2021 at 11:33 AM Bob H. <bob@...> wrote:

Hi all,

After sitting for a couple of years, I'm working on getting Dad's '51 wagon back on the road (and to Wauseon next week!).

Both of the front wheel cylinders were leaking and one was seized. So, I replaced them both and bled the system. Once done, I (think I) followed the service manual brake adjustment steps and took it down the road. It's immediately obvious that the car is pulling badly to the right and it takes very little pedal travel in order to engage a LOT of stopping power.

My son and I put it back up on jack stands and observe the following. While I'm spinning a front wheel forward, he very slowly/lightly applies brake pressure. Just a second or two after I start to feel the linings contact the drum, the wheel STOPS. I mean, it stops like it hit something. The front passenger side is worse than the front driver's side but both exhibit this behavior. When I spin either front wheel backwards, they slow and stop smoothly as they should. The rears, which I didn't touch, slow and stop smoothly as they should in both directions. My son noted that it took more pedal travel to engage the rears, but of course I don't know when the last time the rears were adjusted (and I'm not inclined to touch them at this point!).

I'm going to try adjusting the fronts again but is there a particular mistake during adjustment or procedure that can cause this? I suspect that maybe contact with the drum is causing one of the linings to "shift" in such a way that it is suddenly pushed against the drum with great force.

Thanks! I'm looking forward to my second real Crosley meet!

-Bob Hodgeman


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